1. Field of the Invention
The invention relates generally to automatic clothes dryers. In one aspect, the invention relates to a blower assembly for an automatic clothes dryer utilizing a variable-speed blower motor. In another aspect, the invention relates to a method for adjusting the air flow rate through an automatic clothes dryer drum.
2. Description of the Related Art
Automatic clothes dryers are well known, and typically comprise a cabinet enclosing a horizontally rotating drum for holding items to be dried and accessible through an access door at the front of the cabinet. The drum is rotated by a first belt which is driven by a motor. The motor also drives a blower or fan directly by a shaft connection or by a second belt; the blower delivers dry, heated or unheated air to the drum for drying the items, and exhausts humid air from the drum to a discharge location exterior of the cabinet. The motor and blower assembly are typically mounted in a lower portion of the cabinet beneath or to the side of the drum. The belts are driven by pulleys attached to a rotating shaft of the motor, generally at opposite ends of the motor.
The motor typically rotates at a preselected angular velocity based to achieve a prescribed operational angular velocity for the dryer drum. The angular velocity of the blower is thus linked to the angular velocity of the dryer drum. The angular velocity of the drum is generally maintained constant in order to impart a desired tumbling action to the dryer load, so that the angular velocity of the blower cannot be adjusted during the drying cycle. In other words, the speed of the motor is fixed, which means the blower speed is also fixed. As such, the air flow rate through the drum cannot be varied in response to changes in conditions within the drum such as: load size, type of garment being dried, and initial moisture content of the load; or to user imposed conditions such as pre-selected dryer cycle settings or differences in consumer exhaust vent conditions. Currently, only the heat and cycle time can be varied in response to a change in the conditions. The ability to alter the air flow rate independently of the angular velocity of the drum would provide for additional control over the drying cycle, without negatively impacting clothes load tumbling, which is highly desirable.